import java.util.jar.Attributes
import java.util.jar.JarFile

File artifact = new File(basedir, "target/jetty-runner.jar")
assert artifact.exists()

JarFile jar = new JarFile(artifact);

Attributes manifest = jar.getManifest().getMainAttributes();

assert manifest.getValue(new Attributes.Name("Main-Class")).equals("org.eclipse.jetty.ee9.runner.Runner")
